1. Technical Field
The present Invention relates to an improvement of a double row bearing apparatus for Journalling rotational members of equipment such as motors including rotating portions.
2. Description of the Prior Art
In the prior art, there is a bearing apparatus for Journalling the rotational members of equipments such as motors or generators including rotating portion. The one of bearing apparatus Includes a pair of ball bearings 21, 22 assembled with a shaft 23, as shown in FIG. 3.
In this bearing, the ball bearings 21, 22 are spaced apart by means of spacer 24 secured in the shaft 23.
In the equipment such as a motor of a hard disk drive device to which a bearing apparatus Is to be Incorporated, it Is desirable to make It as compact as possible. In this connection, it is also desirable to reduce the size of the bearing apparatus Itself.
The way which can be adopted to reduce the size of the bearing apparatus Is to miniaturize both ball bearings of the pair. However, this countermeasure leads to the reduction of the diameter of the shaft.
The shaft of reduced diameter provides a problem of reduced rigidity thereof to impair the endurance of the device to which the bearing apparatus is to be incorporated. Further, the shaft of reduced diameter also reduces the rigidity thereof to reduce the resonance-proof property. In this connection, In case such bearing apparatus is to be employed in the precision rotating equipment such as the hard disk drive device, it becomes resonant with members of the equipment surrounding therearound e.g. the casing of the equipment. That is, the reduction of the resonanceproof property will be accompanied by the reduction of the reliability of the equipment.
Accordingly the object of the present Invention is to provide a compact enough double row bearing apparatus having a shaft of sufficient strength and rigidity.